/ˌsɛfəˈlɒsɪst/; /ˌsɛfəˈlɒkɪst/ (sĕfə-lōsist; sĕfə-lōkist)

Definitions

1. noun

A congenital abnormality of the brain, characterized by a cyst or fluid-filled sac on the surface of the brain.

“The doctor explained to the parents that their child had a cephacyst, a rare condition that required immediate surgery.”

2. noun

A cyst or sac on the surface of the brain.

“The MRI scan revealed a cephacyst on the patient’s brain, which had been causing severe headaches.”